Among the many Callinectes spp. across the western Atlantic, the blue crab C. sapidus has the broadest latitudinal distribution, encompassing both tropical and temperate climates. Its life history varies latitudinally, from extended overwintering at high latitudes to year-round activity in tropical locations. Callinectes sapidus reovirus 1 (CsRV1) is a pathogenic virus first described in North Atlantic C. sapidus and has recently been detected in southern Brazil. Little information exists about CsRV1 prevalence at intervening latitudes or in overwintering blue crabs. Using a quantitative reverse transcription PCR (RT-qPCR) method, this study investigated CsRV1 prevalence in C. sapidus across latitudinal differences in temperature and crab life history, as well as in additional Callinectes spp. and within overwintering C. sapidus. CsRV1 prevalence in C. sapidus was significantly correlated with high water temperature and blue crab winter dormancy. Prevalence of CsRV1 in C. sapidus on the mid-Atlantic coast was significantly lower in winter than in summer. CsRV1 infections were not detected in other Callinectes spp. These findings revealed that CsRV1 is present in C. sapidus across their range, but not in other Callinectes species, with prevalence associated with temperature and host life history. Such information helps us to better understand the underlying mechanisms that drive marine virus dynamics under changing environmental conditions.

Long-distance dispersal is one of the main drivers structuring the distribution of marine biodiversity. This study reports the first occurrence of Macrocystis pyrifera and Durvillaea antarctica rafts on the southwestern warm temperate coast of the Atlantic Ocean. Our results indicate that an extreme meteo-oceanographic event, characterized by a northward, displacement of cold sub-Antarctic oceanic waters driven by an extratropical cyclone, could account for these unusual occurrences. A niche model based on known current distribution and maximum entropy principle (MAXENT), revealed the availability of suitable habitats at lower latitudes, outside their actual distribution edges. The distributional boundaries, mainly driven by temperature and irradiance, suggest the existence of environmental suitability in warm temperate areas, as well as in the Northern Hemisphere off Atlantic and Asian coasts. These theoretical edges and respective environmental drivers agree with the physiological affinities of both species, supporting the hypothesis that these variables act as limiting factors for their occurrences in tropical or warmer areas. Emerging regions can function as Diversity 2018, 10, 11; doi:10.3390/d10010011 www.mdpi.com/journal/diversity Diversity 2018, 10, 11 2 of 25 refuges and stepping-stones, providing substrate with adequate habitat conditions for recruitment of propagules, allowing eventual colonization. Long dispersal events reinforce the need for an extensive discussion on selective management of natural dispersion, biological invasions, refuge mapping and conservation initiatives in a transnational perspective.

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KruK, Carla (1,2); Martínez, ana (3); Martínez de la esCalera, Gabriela (4); trinChin, roMina (5); Manta, Gastón (5); seGura, anGel M. (6); PiCCini, Claudia (4); brena, beatriz (7); Fabiano, GraCiela (3,8); Pirez, MaCarena (9); Gabito, lourdes (2); alCántara, iGnaCio (2); YanniCelli, beatriz (2) (1) instituto de eColoGía Y CienCias aMbientales, FaCultad de CienCias, udelar, Montevideo, uruGuaY (2) eColoGía FunCional de sisteMas aCuátiCos, Centro universitario reGional del este (Cure), udelar, roCha, uruGuaY. (3) direCCión naCional de reCursos aCuátiCos, la PaloMa, MGaP, roCha, uruGuaY. (4) dePartaMento de MiCrobioloGía, instituto de investiGaCiones biolóGiCas CleMente estable, MeC, Montevideo, uruGuaY,

The pink shrimp Farfantepenaeus paulensis (Pérez Farfante, 1967) is distributed along the Atlantic Coast from Bahia (Brazil) to Mar del Plata (Argentina). The larval stages enter the Uruguayan brackish water lagoons during late spring to summer associated with tidal currents of the Brazilian Current. In such environments the growth is accelerated and in early autumn the individuals attain commercial size, supporting important regional artisanal fisheries. The pink shrimp catches from 1988 to 2013 were analyzed and related to phenomena of climate variability in ENSO events and to the growth of the species. The total catch ranges from 0.7 to 162 tons. The variation in catches has a negative relationship with the varied climatic events caused by El Niño. Growth parameters yielding values of L ∞ = 177 mm (total carapace length) and K = 1.48 for the period 2009-2013. These values differ slightly from those calculated for natural populations in southern Brazil, suggesting that the population is the same and thus implying the need for coordinated fisheries management between the two countries.